The present invention relates to mechanical sensors, such as capacitive pressure sensors, that have deflectable components. In particular, the present invention relates to a sensor with a deflectable component formed of a titanium-based alloy having an extremely low Young's modulus, an extremely high tensile strength, and stable characteristics over a large temperature range.
Capacitive pressure sensors have found widespread use in industrial, aerospace, and other control and monitoring systems. Capacitive pressure sensors can be configured to sense absolute pressure, gauge pressure, differential pressure, or combinations of those pressures.
Capacitive pressure sensors have been fabricated from a variety of materials, including metal, glass, sapphire, and silicon. The performance of capacitive pressure sensors depends upon the physical characteristics of the material forming the deflectable components of the sensor, such as the center diaphragm of a two chamber capacitive pressure sensor. These physical characteristics include elastic modulus (or Young's modulus), tensile strength of the material, temperature dependence of the elastic modulus and tensile strength, thermal expansion properties, and hysteresis effects.
Other mechanical sensors which rely upon deflection of a sensing component are also affected by the same material properties. There is a continuing need for improvements to capacitive pressure sensors and other mechanical sensors having deflectable sensing components to provide extended operating range, low hysteresis, greater signal-to-noise ratio, reduced correction for temperature effects, and improved stability in temperature hysteresis.